/*
  * RTMP packet utilities
  * Copyright (c) 2009 Kostya Shishkov
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #ifndef AVFORMAT_RTMPPKT_H
 #define AVFORMAT_RTMPPKT_H
 

 #include "libavcodec/bytestream.h"

 #include "avformat.h"

 #include "url.h"

 
 /** maximum possible number of different RTMP channels */

 #define RTMP_CHANNELS 65599

 
 /**
  * channels used to for RTMP packets with different purposes (i.e. data, network
  * control, remote procedure calls, etc.)
  */
 enum RTMPChannel {
     RTMP_NETWORK_CHANNEL = 2,   ///< channel for network-related messages (bandwidth report, ping, etc)
     RTMP_SYSTEM_CHANNEL,        ///< channel for sending server control messages

     RTMP_SOURCE_CHANNEL,        ///< channel for sending a/v to server

     RTMP_VIDEO_CHANNEL = 8,     ///< channel for video data
     RTMP_AUDIO_CHANNEL,         ///< channel for audio data
 };
 
 /**
  * known RTMP packet types
  */
 typedef enum RTMPPacketType {
     RTMP_PT_CHUNK_SIZE   =  1,  ///< chunk size change
     RTMP_PT_BYTES_READ   =  3,  ///< number of bytes read
     RTMP_PT_PING,               ///< ping
     RTMP_PT_SERVER_BW,          ///< server bandwidth
     RTMP_PT_CLIENT_BW,          ///< client bandwidth
     RTMP_PT_AUDIO        =  8,  ///< audio packet
     RTMP_PT_VIDEO,              ///< video packet
     RTMP_PT_FLEX_STREAM  = 15,  ///< Flex shared stream
     RTMP_PT_FLEX_OBJECT,        ///< Flex shared object
     RTMP_PT_FLEX_MESSAGE,       ///< Flex shared message
     RTMP_PT_NOTIFY,             ///< some notification
     RTMP_PT_SHARED_OBJ,         ///< shared object
     RTMP_PT_INVOKE,             ///< invoke some stream action
     RTMP_PT_METADATA     = 22,  ///< FLV metadata
 } RTMPPacketType;
 
 /**
  * possible RTMP packet header sizes
  */
 enum RTMPPacketSize {
     RTMP_PS_TWELVEBYTES = 0, ///< packet has 12-byte header
     RTMP_PS_EIGHTBYTES,      ///< packet has 8-byte header
     RTMP_PS_FOURBYTES,       ///< packet has 4-byte header
     RTMP_PS_ONEBYTE          ///< packet is really a next chunk of a packet
 };
 
 /**
  * structure for holding RTMP packets
  */
 typedef struct RTMPPacket {

     int            channel_id; ///< RTMP channel ID (nothing to do with audio/video channels though)

     RTMPPacketType type;       ///< packet payload type

     uint32_t       timestamp;  ///< packet full timestamp
     uint32_t       ts_delta;   ///< timestamp increment to the previous one in milliseconds (latter only for media packets)

     uint32_t       extra;      ///< probably an additional channel ID used during streaming data
     uint8_t        *data;      ///< packet payload
     int            data_size;  ///< packet payload size
 } RTMPPacket;
 
 /**

  * Create new RTMP packet with given attributes.

  *
  * @param pkt        packet
  * @param channel_id packet channel ID
  * @param type       packet type
  * @param timestamp  packet timestamp
  * @param size       packet size
  * @return zero on success, negative value otherwise
  */
 int ff_rtmp_packet_create(RTMPPacket *pkt, int channel_id, RTMPPacketType type,
                           int timestamp, int size);
 
 /**

  * Free RTMP packet.

  *
  * @param pkt packet
  */
 void ff_rtmp_packet_destroy(RTMPPacket *pkt);
 
 /**

  * Read RTMP packet sent by the server.

  *
  * @param h          reader context
  * @param p          packet
  * @param chunk_size current chunk size
  * @param prev_pkt   previously read packet headers for all channels
  *                   (may be needed for restoring incomplete packet header)

  * @return number of bytes read on success, negative value otherwise

  */
 int ff_rtmp_packet_read(URLContext *h, RTMPPacket *p,
                         int chunk_size, RTMPPacket *prev_pkt);

 /**
  * Read internal RTMP packet sent by the server.
  *
  * @param h          reader context
  * @param p          packet
  * @param chunk_size current chunk size
  * @param prev_pkt   previously read packet headers for all channels
  *                   (may be needed for restoring incomplete packet header)
  * @param c          the first byte already read
  * @return number of bytes read on success, negative value otherwise
  */
 int ff_rtmp_packet_read_internal(URLContext *h, RTMPPacket *p, int chunk_size,
                                  RTMPPacket *prev_pkt, uint8_t c);

 
 /**

  * Send RTMP packet to the server.

  *
  * @param h          reader context
  * @param p          packet to send
  * @param chunk_size current chunk size
  * @param prev_pkt   previously sent packet headers for all channels
  *                   (may be used for packet header compressing)

  * @return number of bytes written on success, negative value otherwise

  */
 int ff_rtmp_packet_write(URLContext *h, RTMPPacket *p,
                          int chunk_size, RTMPPacket *prev_pkt);
 
 /**

  * Print information and contents of RTMP packet.

  *

  * @param ctx        output context

  * @param p          packet to dump
  */
 void ff_rtmp_packet_dump(void *ctx, RTMPPacket *p);
 
 /**

  * @name Functions used to work with the AMF format (which is also used in .flv)

  * @see amf_* funcs in libavformat/flvdec.c
  * @{
  */
 
 /**

  * Calculate number of bytes taken by first AMF entry in data.

  *
  * @param data input data
  * @param data_end input buffer end
  * @return number of bytes used by first AMF entry
  */
 int ff_amf_tag_size(const uint8_t *data, const uint8_t *data_end);
 
 /**

  * Retrieve value of given AMF object field in string form.

  *
  * @param data     AMF object data
  * @param data_end input buffer end
  * @param name     name of field to retrieve
  * @param dst      buffer for storing result
  * @param dst_size output buffer size
  * @return 0 if search and retrieval succeeded, negative value otherwise
  */
 int ff_amf_get_field_value(const uint8_t *data, const uint8_t *data_end,
                            const uint8_t *name, uint8_t *dst, int dst_size);
 
 /**

  * Write boolean value in AMF format to buffer.

  *
  * @param dst pointer to the input buffer (will be modified)
  * @param val value to write
  */
 void ff_amf_write_bool(uint8_t **dst, int val);
 
 /**

  * Write number in AMF format to buffer.

  *
  * @param dst pointer to the input buffer (will be modified)
  * @param num value to write
  */
 void ff_amf_write_number(uint8_t **dst, double num);
 
 /**

  * Write string in AMF format to buffer.

  *
  * @param dst pointer to the input buffer (will be modified)
  * @param str string to write
  */
 void ff_amf_write_string(uint8_t **dst, const char *str);
 
 /**

  * Write a string consisting of two parts in AMF format to a buffer.
  *
  * @param dst pointer to the input buffer (will be modified)
  * @param str1 first string to write, may be null
  * @param str2 second string to write, may be null
  */
 void ff_amf_write_string2(uint8_t **dst, const char *str1, const char *str2);
 
 /**

  * Write AMF NULL value to buffer.

  *
  * @param dst pointer to the input buffer (will be modified)
  */
 void ff_amf_write_null(uint8_t **dst);
 
 /**

  * Write marker for AMF object to buffer.

  *
  * @param dst pointer to the input buffer (will be modified)
  */
 void ff_amf_write_object_start(uint8_t **dst);
 
 /**

  * Write string used as field name in AMF object to buffer.

  *
  * @param dst pointer to the input buffer (will be modified)
  * @param str string to write
  */
 void ff_amf_write_field_name(uint8_t **dst, const char *str);
 
 /**

  * Write marker for end of AMF object to buffer.

  *
  * @param dst pointer to the input buffer (will be modified)
  */
 void ff_amf_write_object_end(uint8_t **dst);
 

 /**
  * Read AMF boolean value.
  *
  *@param[in,out] gbc GetByteContext initialized with AMF-formatted data
  *@param[out]    val 0 or 1
  *@return 0 on success or an AVERROR code on failure
 */
 int ff_amf_read_bool(GetByteContext *gbc, int *val);
 
 /**
  * Read AMF number value.
  *
  *@param[in,out] gbc GetByteContext initialized with AMF-formatted data
  *@param[out]    val read value
  *@return 0 on success or an AVERROR code on failure
 */
 int ff_amf_read_number(GetByteContext *gbc, double *val);
 
 /**
  * Read AMF string value.
  *

  * Appends a trailing null byte to output string in order to

  * ease later parsing.
  *
  *@param[in,out] gbc     GetByteContext initialized with AMF-formatted data
  *@param[out]    str     read string
  *@param[in]     strsize buffer size available to store the read string
  *@param[out]    length  read string length
  *@return 0 on success or an AVERROR code on failure
 */
 int ff_amf_read_string(GetByteContext *gbc, uint8_t *str,
                        int strsize, int *length);
 
 /**
  * Read AMF NULL value.
  *
  *@param[in,out] gbc GetByteContext initialized with AMF-formatted data
  *@return 0 on success or an AVERROR code on failure
 */
 int ff_amf_read_null(GetByteContext *gbc);
 
 

 /** @} */ // AMF funcs
 
 #endif /* AVFORMAT_RTMPPKT_H */